Gabuza, who replaced Tendai Ndoro late in the quarter-final, nodded home a cross from Thabo Rakhale in the 103rd minute to give Bucs a 2-1 victory on Saturday after 90 minutes produced a 1-1 stalemate at Orlando Stadium.
Gabuza has played second fiddle to Golden Boot contender Ndoro at Mayfair this campaign, having yet to score in 12 league outings (three starts).
However, the former Golden Arrows hitman also netted in Pirates' Nedbank Cup opener against Eastern Cape Bees FC in March, and appears to enjoy support from Jonevret.
"I'm very pleased with Gabuza because Ndoro did absolutely well in 75 minutes or 70 minutes and it was good," said Jonevret, who linked up with the Sea Robbers in February.
"But when you are one-nil up and it's 15 or 20 minutes left it's nice to have a boy like Gabuza who can keep the ball a little longer, because we lost the ball too quick there [upfront]. Maybe Ndoro's stronger side is not to keep the ball.
"I'm very happy for him [Gabuza], it has been a tough time for him and he hasn't played that much. But it was a nice goal and it's important for strikers to score. So now that he can score we don't have to talk about he can't do that. But it was good and it was a cross from Rakhale also."
The Swede was also impressed with Rakhale's commitment on his return from a lengthy layoff through injury.
"First of all, Rakhale I haven't seen on TV before I came here because he was injured when I arrived here. He has been out injured for a long period of time," added Jonevret.
"But at training he has worked hard and unfortunately [Thembinkosi] Lorch didn't play and maybe, I don't know if it's a long period, but it could be. I talked to other ones and Rakhale has been good at training.
"At least he was out there fighting for 120 minutes and that was a little bit surprising for me, but you saw he was a little bit rusty sometimes."